THURSDAY, July 19 (HealthDay News) -- The first glimmer of hope for a cure for HIV came in 1996 with the advent of powerful drug cocktails known as highly active antiretroviral therapy (HAART). But the feeling was short-lived.

While HAART has drastically reduced deaths due to AIDS and other HIV-related diseases, it is no cure -- if patients stop taking the medications (because of side effects or other reasons), the virus bounces right back, as a 2010 study of patients in Latin America and the Caribbean showed.

Yet, there is now a renewed sense of promise that, even if it still years away, researchers have a better understanding of targets that could lead to a cure, said Rowena Johnston, vice president and director of research at the Foundation for AIDS Research. "We are seeing something that is probably a lot like that time in the 1990s," she said.

In 2012, new causes for optimism include approval of a new drug, Truvada, that can help prevent the spread of HIV, safer and more effective drugs to treat those who are infected and better efforts to diagnose HIV/AIDS in people who don't realize they have it.

These and other achievements will be a focus at the biennial International AIDS Conference, held this year in Washington, D.C. The meeting, which begins Sunday, has not been held in the United States in 22 years. Its return stems from the Obama administration's decision in 2009 to end the ban on HIV-positive people entering the country, Johnston said.

Hints at a cure

Another "large part of the basis for the new optimism" comes from the experience of one patient back in 2008, Johnston said. That was Timothy Brown, also known as "the Berlin patient," who was pronounced cured of HIV by his doctors.

The cure involved a special kind of blood transplant that Brown received for his leukemia from a donor that happened to have rare, mutant cells that did not allow HIV to take hold. This procedure is "absolutely not practical" for the general population, Johnston said, but it has launched research looking at ways to mimic the effect, by using gene therapy to make a patient's cells resistant to HIV.

"[But] if we are going to bring about an 'AIDS-free generation,' as [then] Senator Hilary Clinton said, we are also going to need to decrease the number of new HIV cases and bring that number down to zero," Johnston said.

That's a lofty goal, since more than 1 million people in the United States remain infected with HIV, according to estimates by the U.S. Centers for Disease Control and Prevention. There are also about 50,000 new cases of HIV every year and that number hasn't budged over the past two decades.

"On the prevention side, the excitement is all around use of antiretroviral therapy," said Dr. Sten Vermund, director of the Vanderbilt Institute for Global Health in Nashville, Tenn.

For example, one 2011 study showed that treating patients with antiretroviral therapy early -- before HIV had weakened their immune system -- not only kept the patients healthier, it reduced the risk that their uninfected sexual partners would become infected by 96 percent. "That's as good as condoms," Vermund noted, although experts are quick to stress that no medication should be seen as a substitute for the condom.

Partly because of that study, the U.S. Department of Health and Human Services in March 2012 recommended that doctors prescribe antiretroviral therapy for all HIV patients, even if their immune system is strong, as long as they can commit to the daily medication regime.

Using treatment as prevention

Taking the use of antiretroviral therapy for prevention a step further, the U.S. Food and Drug Administration on Monday approved Truvada (an anti-HIV drug already used as treatment) for people uninfected with HIV but at high risk of becoming infected -- making it the first medication to help prevent infection.

However, some experts argue that people taking Truvada for HIV prevention will forego condoms or that improper use of Truvada could lead to the emergence of resistant strains of HIV.

There's also headway being made in improving access and uptake of HIV testing. The goal: "Radically expanding testing so we don't have people who don't know their HIV status, and if you are HIV-positive, you are [then] linked to effective care," Vermund said.

Experts estimate that about one in five people who has HIV does not know it and three recent studies, including one by Vermund and his colleagues, found that only about one-quarter of people with HIV are keeping the virus in check with antiretroviral drugs. Data like that was "a wake-up call" that more needed to be done, Vermund said.

There's good reason to find out your HIV status early, since newer antiretroviral drugs now carry lower risk of side effects, noted Stephen Gange, a professor of epidemiology at Johns Hopkins University, in Baltimore. "I think everyone felt comfortable that they could be used fairly widely," he said.

Another milestone in HIV/AIDS care was achieved earlier this month, when the FDA approved the OraQuick In-Home HIV Test, the first test that can give a person rapid results on his or her HIV status in the privacy of their own home.

Better access to testing, better outcomes

San Francisco may be ahead of the curve in testing and treating, Vermund said. In 2010, the city announced that any resident living with HIV would be directed to antiretroviral therapy even before they show signs of advancing disease. New York is the only other city to have announced this policy, in December 2011.

Since 2010, the San Francisco Department of Public Health has intensified its efforts on routine HIV testing in emergency rooms, doctors offices and storefront testing sites in high-prevalence neighborhoods, unless patients want to opt out, said Dr. Moupali Das, director of research for the department's HIV Prevention Section. And if a person tests positive for HIV, the testing site and clinic now communicate with each other to ensure the person receives care, she added.

The result: the proportion of gay and bisexual men who did not know they were HIV-positive has dropped from about 20 percent in 2004 to only 8 percent in 2011, Das said.

"HIV in the U.S. is not a homogenous epidemic. It's lots of tiny little epidemics affecting different groups of people and different geographies in different ways," Das said.

In the United States, HIV has the biggest impact on gay and bisexual men. Black men in this group make up a quarter of new HIV cases. Among women infected HIV, black and Hispanic women made up more than three-fourths of new cases in 2005.

A new study is under way in the Bronx, in New York City, and in Washington to promote testing in these areas, with special messages for gay and bisexual men, and to determine whether incentives like receiving gift cards make people more likely to visit their clinic and take their medication as directed.

"Like many others, I would be delighted to have an AIDS-free generation, but I think we really need to think that we can't rely on [only] one strategy," Ganges said.

Renewed optimism

In the meantime, researchers seeking to adapt the cure of the "Berlin patient" are still in the early stages of trying to figure out how to target the appropriate cells without harming others, Johnston said.

A vaccine for HIV also remains a possibility, although no one expects it anytime soon. One 2009 vaccine trial in Thailand reduced HIV infection rates by about 30 percent, which is the first evidence that an HIV vaccine might be effective, said Rick King, vice president of AIDS vaccine design at the International AIDS Vaccine Initiative, in New York City.

More studies have to be done to get a better idea of how much protection this vaccine offers, as well as whether it would work in populations like the United States. But even if it all goes smoothly, it would probably be close to 10 years before this vaccine were deployed to the public, King said.

To keep pessimism from setting in as it did after HAART turned out not to be the end-all-be-all, people should think of eradicating HIV in stages, Gange said. "I think first it would make sense to see strategies for bringing rates of HIV infection down 50 percent or 90 percent and that would be great, and then reevaluate," he said.

The news about Truvada and the data on preventing HIV transmission by early antiretroviral therapy are great, Gange said. "These are encouraging and give us a set of phase-one strategies."